[capev86]

stock q-jets are excellent for fuel mileage if in good shape and tuned properly. i am currently building up an 84 q-jet with edelbrock guts to throw on my 72 burb. big blocks are heavy and naturally thirsty due to displacement and you may also be fighting the gearing, etc that the truck is set up with. you need an overdrive and a 4.10 or softer rear for modern driving. also, if you are driving in traffic or at low or high speeds you are not realizing the best economy the vehicle is capable of. that vehicle is gonna get best mileage at a steady 40 to 50mph. even modern trucks with fuel injection and overdrive get drastically better mileage if you keep the speed at 60 or under. trucks push a lot of air out of the way as well as move a lot of weight so gentler speeds are a must for gas savings. my 72 burb 3/4 ton 2wd has a measly 307 with 3 on the tree and 4.57 rear gear and the best mileage i have gotten is 10-11mpg on mixed driving. i try hard to keep it to around 50 on the highway, especially since the engine is screaming. i have a 4.10 rear gear ready to go in and eventually plan to add the factory OD to the saginaw and that should get me closer to the 18mpg that my dad's 87 burb gets.